Electric switch



- Dec. 30, 1941. H". B. DRAPEAU ELECTRIC 'SWITCH Filed Sept. 19, 1939 @Gamm Patented Dec. 30, i941 ELECTRIC SWITCH Harold B. Drapeau, Oak Park, Ill., assignor to The Dole Valve Company, Chicago, lll., a corporation of Illinois Application September 19, 1939, Serial No. 295,653

'(Cl. 20o-138) 6Claims.

This invention-relates to electric switches and has for its object to provide a new and improved device of this description.

The invention has as a further object to provide an electric switch which maybe arranged either to open a circuit or close a circuit in response to variations in temperature. 'I'he lnvention has as a further object to provide an electric switch embodying a b imetal thermostatlc element which acts either to normally hold the circuit closed or to normally hold it open and then under a predetermined rise in temperature, to move so as to cause the circuit to be opened or to be closed;

The invention hasl as a further object toprovide an electric switch of this description wherein the bimetal thermostatic element engages a nonconducting member.` The invention has a further object to provide an electric switch of the kind described, with adustable means for adjusting this non-conducting member engaged bythe bimetal thermostatic element.

The invention has further objects which are more particularly pointed out in the accompanying description.

Referring now to the drawing, Fig. 1 is a plan view of one form of the device embodying the invention, with the top removed;

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1, with the top in position; l

Fig. 3 is asectional view taken on line 3-3 of Fig. 1, with the top in position;

Fig. 4 is a detailed view showing the adjusting means;

Fig. 5 is a sectional view showing a modied construction.

Like numerals refer to like parts throughout the several gures.

Referring now to the drawing, I have shown in Figs. 1 to 4 one form of switch embodying the invention. In this construction there is a switch housing or casing I which is preferably provided with a screw threaded portion 2 by means of which it may be supported in position. Connected with the switch casing is Va hollow member I which may be attached to the casing in any desired manner, as bysolderlng. Located withing the casing is a bimetal thermostatic strip I which has its end 5 xed to the member 3 and which projects up into thefenlarged part 6 of the casing, which is hollow and contains other parts of the switch. The hollow projecting part oi' the casing is closed at its lower end and is preferably sealed so as to be non-leaking. The enlarged part 6 is provided with the annular member Ia over which fits a cover 6b. The bimetal strip l may be made in any of the usual ways from two pieces of metal having different coeiiicients of expansion.

The upper end of the bimetal strip 4 engages a member 'I which is of any suitable vnon-conducting material. The member 'I is connected to one member 'Ia of a looped spring 8, which has the other member 9 fastened to a xed part I0 in the casing. 'I'he member 'Ia of this spring carries an electrical contact II which cooperates with an elctrical contact I2 attached to the member I3, electrically connected to the conducing member I l with which is connected an electrical conductor I5. A

The non-conducting member 'I is preferably, adjustably connected to the spring 8 so that it may be moved to increase or decrease the portion thereof which projects beyond the thermo- 20- static element I. In the construction herein shown this adjustment is arranged so that it may be easily and quickly made and so that the member 1 may be moved a very small amount in either direction at any given adjustment. In the construction shown, in order to secure this adjustment. there is a member which has a head I6 provided with a tool receiving notch Ita, and a body II which passes through the spring and is connected to the member 'I in any suitable manner, as by means oi the piece I'Ia connected to the body il.. The body I1 is eccentrically connected with the head iS, as shown in Fig. 4, so that as the adusting member is turned, the member Z1 will he moved ioaesward or forward, depending upon the direction of rotation of the head. When it is desired 'to have the circuit open at a lower temperature, the adjusting member is moved so as bring the iree end of the member I nearer to the thermostatic element 4 and when it is desired that the circuit be opened at a higher temperature, the adjusting device is moved to move the free end of the member 'I farther away from the end of the thermostatic element t. The contact II and 'the spring 8 are connected with a conducting member I8; to which is connected a conductor I9. 'I'he conductors I5 and I9 may be electrically connected to the contacts II and I2 in any desired manner. As herein shown, the parts I I and I8 are illustrated as binding posts and the conductors are held in contact therewith by the binding post nuts Isa.

The contacts II and I2 when closed, complete a circuit between the conductors I5 and I9 and when opened. break this circuit. Under normal conditions these contacts ii and l2 are held together as shown in Fig. 2, so as to complete the circuit. When the temperature to which the bimetal thermostatic element d is `sub;lected,

reaches a predetermined point, the thermostatic element bends to the left se as to release the member f5. Whenthis is done the spring member 1a, which has been prevented from acting by the thermostatic element d, then acts to move the contact il away from the contact i2` and open' the circuit. This spring member moves down when released, so as to move down past the upper end of the bimetal element d and the circuit can then only be completed by the intervention of some individual, and'even with the intervention of an individual can only be completed after the temperature of the thermostatic element has lowered to a predetermined amount. Y

There is' illustrated one means of reestablishing the circuit, which consists of a resetting member 20 which is provided with a retracting spring 2| and which engages the end 22 of a lever pivoted at 23, the other end i of which passes under themember 'l or the member la of the spring 8, so that when the resetting member 2i is pressed, the member t3 will move the member l to bring contacts il and i2 together and permit the thermostatic element to move in under the member 'Iy to its initial position, as shown in Fig. 2.

In Fig. 5 there is illustrated a construction where the contacts of the switch are normally open and are closed when the temperature reach- -to the member i3, that is by reversing their positions, shown in Fig. 1. The contact i2 is connected in circuit by the conductorioi and the contact Ii is connected in circuit bythe conductor ila. It will be seen that the thermostatic element l when in the position shown in Fig. 5, holds the contacts il and i2 apart. When the thermostatic element is heated to a predetermined degree, the top portion of it then moves to the left and releases the member il so that the spring t moves contact il to bring it in contact with contact i2 and complete the circuit. The member i is provided with adjusting mechanism like that shown in Figs. l, 2 and 3. When the thermostatic element d is cooled sufhciently, the parts are returned to their normal position by the same resetting mechanism shown in Figs. l and 2, which when the resetting member t is pressed, moves the member l and separates the contacts i! and i2, the member l being moved sufficiently to permit the thermostatic element 8 to move in under 'it as shown in Fig. 5.

ment I is to be acted upon by liquid cr gas, the

switch is inserted in position so that the part 3 projects into the liquid or gaaithat is, so that the liquid or gas comes in contact with the part 3. It is preferred to have the part 3 aclosed device so vthat the liquid or gas will not comel directly in contact with the bimetal element 4, so as not to corrode any of the working parts of the switch. It is ofcourse evident that the switch may be used in any position where such a switch is applicable.

I initial position until it is cooled, and from ofI When theV switch shown in Figs. 1 to i is in proper position, the contacts il and i2 are closed. When the temperature of the thermostatic element 4 reaches a predetermined point, the upper end of the bimetal element will be moved tothe left so as to move out from under the member 1. The spring 8 then moves the member i down, which carries with it the contact il, thus breaking the circuit between the contacts li and i2. When the member 'i is in this position, it is in a position to prevent the thermostatic element d from being moved back to its itself moving back to its initial position after it is cooled to the predetermined temperature. It will thus be seen that-this device automatically breaks the circuit and maintains the circuit broken until the thermostatic device fi hasv cooled sumciently and until it is manually reset. The switch is applicable to any condition where it is desirable to have the circuit thus automatically broken, as, 'for example, where unless the circuit .was broken, injury might result to Asome parts which it is desired to have protected from injury by this means. y After the thermostatic element has cooled sumciently, the circuit may be again completed by moving the resetting element 2U, which by means of the end 24. of the resetting lever, moves the member 'i to permit the thermostatic element i to move in under it to its initial position, this movement of the member 'i v l i prevents the return of the thermostatic element to its initia1 position and it can only be returned to its initial position after the temperature has lowered to a predetermined point, and then only by means of the manual resetting device.

I claim:

l. An electric switch comprising a casing, two opposed cooperating contacts mounted therein, a spring with which one of said contacts is connected, a non-conducting element connected with said spring, and a ilat straight bimetal thermostatic element within said casing, having one end connected to one end oi the casing, the other end being free and extending in proximity to the other end of the casing, the free end oi the thermostatic element normally engaging one face of the non-conducting element, the bimetal thermostatic element and the portion ci' the non-conducting element engaged by the thermostatic element being in alignment when the bimetal thermostatic element is in its normal position, which bimetal thermostatic element normally holds thehun-conducting element in its normal initial position, the engaging end of said bimetal thermostatic element when the temperature` reaches a predetermined point, moving along the face of said non-conducting element to a position to release the non-conducting element and the spring to cause said contacts to move relatively.

2. An electric switch comprising a casing, two opposed cooperating contacts mounted therein, a spring with which one of said contacts is conment. with said spring, a fiat straight bimetal thermostatic element which normally holds the non-conducting element in its normal initial position, said bimetal thermostatic element when the temperature reaches a predetermined point, moving to a position to release the non-conducting element and the spring to cause said contacts to move relatively, said connecting -device for connecting said non-conducting element with said spring also forming an adjusting device for said non-conducting element, to adjust 'its position with relation to said bimetal thermostatic element, to changey the temperature at .which the non-conducting element and spring are released.

3. An electric switch comprising a casing, two opposed cooperating contacts mounted therein, a spring with which one of said contacts is connected, a non-conducting element, a connecting device for connecting said non-conducting element with said spring, a flat straight bimetal thermostatic element -which normallyholds the non-conducting element in its normal initial position, said bimetal thermostatic element' when the temperature reaches a 'predetermined point, moving to a position to release the non-conducting element and the-spring to cause said contacts to move relatively, said connecting device for connecting said non-conducting element with said spring also forming an adjusting device for said non-conducting element, to adjust its position with relation to said bimetal thermostatic element, to change the temperature at which the non-conducting element and spring are released, said adjusting device comprising a head and a body portion passing through said spring and connected with said non-conducting element, said body portion being eccentrlcally connected with said head.

4. An electric switch comprising a casing, two opposed cooperating contacts mounted therein, a spring with which one of said contacts is connected, a non-conducting element connectedl with said spring, a ilat straight bimetal thermostatic element within said casing. having one end connected to one end of the casing, the other end being free and extending inproximity to the other end oi' the casing, thefree end of the thermostatic element normally engaging one face o! the non-conducting element. the bimetal thermostatic element, the two contacts and the portion of the non-conducting element engaged by the thermostatic element being in alignment when the bimetal thermostaticelement is in its normal position, which bimetal thermostatic element normally holds the non-conducting element in its normal initial position, the engaging end oi said bimetal thermostaticv element when the temperature reaches a predetermined point, moving along the face of said non-conducting element to a position to release the nonconducting element and the spring to cause said contacts to move relatively, and a casing having a hollow projecting part, closed at one end, into which said bimetal thermostatic element is received, said casing having an enlargement into which the bimetal thermostatic element projects, said contacts and spring being located in. said enlargement, the movement oi' said bimetal thermostatic element causing a relative movement oi the contacts towards each other.

5. An electric switch comprising a casing, two opposed cooperating contacts mounted therein and normally in engagement to complete a circuit, a spring with which one of said contacts is connected. a flat straight non-conducting element connected with said spring, a bimetalthermostatic element within' said casing, having one when the bimetal thermostatic element is in its normal position, which bimetal thermostatic ele-` ment normally holds the non-conducting element in its normal initial position and the contacts in electrical engagement, the engaging end of said bimetal thermostatic element when the temperature reaches a predetermined point, moving along the face of said non-conducting element to a i position to release the non-conducting element of said contacts is connected, a non-conducting.

and the .spring to cause said contacts to be separated to break the electric circuit.

8. An electric switch comprising two opposed cooperating contacts, a spring with which one element connected with said spring, a bimetal thermostatic element which normally holds the non-conducting element in its normal initial position, said bimetal thermostatic element when the temperature reaches a predetermined point, moving to a position to release the non-conducting element and 4the spring to cause said contacts to move relatively to close the circuit, said.

bimetal thermostatic element belng'held in its released lposition by said non-conducting ele- 4ment, and a manual resetting device for resetting the parts to their initial positions, comprising a pivoted lever, a movable resetting member engaging one end o! the pivoted lever, the other end of the pivoted lever when moved, moving said non-conducting element to moveit and its associated contact to their initial posiitons, so ask to free the bimetal thermostatic element so it can vmove to its initial position.

HAROLD n. DRAPEAU. 

